How to fix CVE-2025-59835?

Within 24 hours: Identify all LangBot instances and their current versions. Within 7 days: Upgrade all affected deployments to LangBot 4.3.5 or later. Within 30 days: Conduct access reviews on user accounts with API credentials and implement file upload logging to detect past exploitation attempts.

CVE-2025-59835

EUVD-2025-33219 HIGH

2025-10-02 [email protected]

Information Disclosure

8.6

CVSS 4.0

CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Lifecycle Timeline

Analysis Updated

Apr 16, 2026 - 06:26 EUVD-patch-fix

executive_summary

Re-analysis Queued

Apr 16, 2026 - 05:29 backfill_euvd_patch

patch_released

patch_available

Apr 16, 2026 - 05:29 EUVD

4.3.5

EUVD ID Assigned

Mar 13, 2026 - 19:12 euvd

EUVD-2025-33219

Analysis Generated

Mar 13, 2026 - 19:12 vuln.today

CVE Published

Oct 02, 2025 - 19:15 nvd

HIGH 8.6

DescriptionNVD

LangBot is a global IM bot platform designed for LLMs. In versions 4.1.0 up to but not including 4.3.5, authorized attackers can exploit the /api/v1/files/documents interface to perform arbitrary file uploads. Since this interface does not strictly restrict the storage directory of files on the server, it is possible to upload dangerous files to specific system directories. This is fixed in version 4.3.5.

AnalysisAI

Technical ContextAI

Unrestricted file upload allows attackers to upload malicious files (web shells, executables) that can then be executed on the server.

RemediationAI

Validate file types by content (magic bytes), not just extension. Store uploads outside the web root. Use random filenames. Scan uploads for malware.

CVE-2025-59835 vulnerability details – vuln.today

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